diff --git a/README.md b/README.md
index 8ef73c5..1f07129 100644
--- a/README.md
+++ b/README.md
@@ -71,7 +71,7 @@ Connect the peripherals the following way (peripheral signal; peripheral signal;
   - VCC; 24; ; +5V;
   - GND; 12; ; GND;
   - common input; 1; PB6; GPIO; clock for TM1637
-  - #E; 15; PB9; GPIO; to enable on low
+  - -E; 15; PB9; GPIO; to enable on low
   - S0; 10; PB3; GPIO; to select output
   - S1; 11; PB4; GPIO; to select output
   - S2; 14; PB5; GPIO; to select output
@@ -83,9 +83,6 @@ Connect the peripherals the following way (peripheral signal; peripheral signal;
   - I4; 5; 18; CLK; TM1637 for 
   - I5; 4; 18; CLK; TM1637 for 
   - I6; 3; 18; CLK; TM1637 for 
-- 1x tilt sensor
-  - VCC/GNG; ; ; +3.3V;
-  - OUT; ; PA10; WKUP; pulled low, wake up on rising edge
 
 All pins are configured using `define`s in the corresponding source code.
 
diff --git a/lib/i2c_master.c b/lib/i2c_master.c
index 52a9463..2a52863 100644
--- a/lib/i2c_master.c
+++ b/lib/i2c_master.c
@@ -13,7 +13,7 @@
  *
  */
 /** library to communicate using I2C as master (code)
- *  @file i2c_master.h
+ *  @file i2c_master.c
  *  @author King Kévin <kingkevin@cuvoodoo.info>
  *  @date 2017
  *  @note peripherals used: I2C @ref i2c_master_i2c, timer @ref i2c_master_timer
diff --git a/lib/print.h b/lib/print.h
index 79ec704..5a6d3e6 100644
--- a/lib/print.h
+++ b/lib/print.h
@@ -14,7 +14,7 @@
  */
 /** printing utilities to replace the large printf from the standard library (API)
  *  use % as format specifier prefix, followed by + to enforce sign of prefix, 0 and 0-9 for padding, and format specifier
- *  format specifier supported are: c for far, s for string, u for uint32_t, d for int32_t, U for uint64_t, D for int64_t, x for lower case hex up to uint32_t, X for upper case hex up to uint32_t, b for bits up to uint32_t
+ *  format specifier supported are: c for char, s for string, u for uint32_t, d for int32_t, U for uint64_t, D for int64_t, x for lower case hex up to uint32_t, X for upper case hex up to uint32_t, b for bits up to uint32_t
  *  @file print.h
  *  @author King Kévin <kingkevin@cuvoodoo.info>
  *  @date 2017
diff --git a/main.c b/main.c
index c806276..aaee92d 100644
--- a/main.c
+++ b/main.c
@@ -12,10 +12,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  */
-/** STM32F1 example
+/** CuVoodoo clapperboard firmware (for STM32F103Cx micro-controller)
  *  @file main.c
  *  @author King Kévin <kingkevin@cuvoodoo.info>
- *  @date 2016
+ *  @date 2016-2017
  */
 
 /* standard libraries */
@@ -189,6 +189,9 @@ error:
 	return;
 }
 
+/** select output for TM1637 display using the multiplexer
+ *  @param[in] output clock output
+ */
 static void mux_select(uint8_t output)
 {
 	if (output>7) { // multiplexer is only controlling 8 outputs